TABLE OF CONTENTS
I) General Description ............................................................................. 2
II) Features ............................................................................................... 2
III) Features Illustration ........................................................................... 3
IV) Operation ............................................................................................ 4
V) Theory of Operation ........................................................................... 7
VI) Specifications .................................................................................... 8
I) GENERAL DESCRIPTION
II) FEATURES
The
is a regulated linear power supply which produces a 13.8
VDC output from either a 115 or 230 VAC input. It incorporates a built-in
battery which will continue to supply the 12 volt load with DC power in the
event of a temporary loss of AC input to the supply. Provision is made for
increasing the amount of time available for operating on emergency back-
Power-Pac
up with the addition of another internal or external battery.
Regulated Noise-free Output
The Power-Pac features a highly regulated,
low ripple output (see specifications) to power radios and other sensitive
communications equipment without causing RF or audio interference.
Battery Back-up
A 7 amp-hour battery is built into the unit to provide up to
20 amps of emergency transmit power. It is charged automatically by the output
of the Power-Pac during normal operation. In addition, mounting space and
battery terminals are provided within the unit for an optional second 7 amp-hour
battery (available from NEWMAR), thus allowing the operator to double the
amount of time that the radio can operate on emergency power. If more back-
up power is desired, terminals are provided for the addition of an external battery.
Battery and Input/Output Status Indicators
The operator is kept informed
of all important functions such as AC input, DC output and battery status with
front-panel indicator lights and a warning buzzer.
Automatic Low Battery Disconnect
The battery is protected against
damage from extreme discharge by a circuit which will automatically disconnect
the load when output voltage reaches 10.3 VDC.
Over-Voltage Protection
The radio being powered is protected against
damage from any condition which might cause excessive output voltage by an
over-voltage protection (OVP) circuit.
2
7
Should emergency communication be necessary after this automatic shut-down,
the Power-Pac provides a Shut-down Override Button. This button, when
pressed, reconnects the battery to the radio or other communication load. This
reconnect circuit works only when the Override Button is being pressed.
Disconnect occurs when it is released.
Batteries may be permanently
damaged by being re-engaged with the Override Button.
Note:
If the Power-Pac is already connected to the radio when AC power fails,
engagement of the battery back-up is automatic. However, there may be
occasion to install the Power-Pac when there is no AC power available initially.
In this case, it will be necessary to position the On/Off switch to “On” and then
press the Override Button once to engage the battery back-up.
V) THEORY OF OPERATION
AC
Input
5 Amp Power Supply
S1
AC “ON”
Indicator
Crowbar
SCR
Battery
Status and
Low Voltage
Disconnect
Solid State
Relay
S2
Battery Status
LED
“NORMAL” LED
Buzzer and
Silence Switch
Out, 13.8 VDC
External Battery
Out
5. Buzzer
When battery output voltage reaches the point where the Battery
Status light begins to flash, at the same time an audible Buzzer will begin to
sound. If desired, this automatic Buzzer may be disabled by positioning the
Buzzer Switch to “Off”.
6. Shut-down Override Button
Because batteries may be permanently
damaged by being completely discharged, particularly if they are left discharged
for a long period of time, the Power-Pac employs an automatic low-voltage
disconnect circuit. If the back-up battery is drained to the point where only 10.3
VDC is sensed at the output terminals, the Power-Pac will automatically
disconnect the load from the battery back-up.